Characterisation of corrosion products on copper-based artefacts: Potential of MA-XRF measurements

The use of macro-X-ray fluorescence (MA-XRF) scanners is now widespread in cultural heritage applications. However, its use for the characterisation of metallic works of art is still limited. In this study, a novel portable MA-XRF scanner prototype was tested on artificially corroded copper samples to assess its analytical capabilities on corroded metals, yielding information on the spatial distribution of the corrosion products grown on the metal's surface. A multi-analytical approach was used to thoroughly characterise the copper samples and compare the obtained results to verify the reliability of the MA-XRF data. The prototype was able to obtain distribution maps of different elements, such as sulphur and chlorine, which can be directly correlated to different corrosion products. With the use of imaging filtering techniques, it was possible to investigate the stratification of the corrosion product layers and observe gradients in the distribution of certain elements.